So the definition of spam is something that is bought cheap?
The point is that it doesn't matter if it's free or paid, if what you pay is near-zero cost. It definitely cannot be a factor of ruling out spam if the fees are too cheap and aren't an adequate deterrent.
And even "adequate deterrent" is wrong, as a term, because a script kiddie might not afford a good spam attack but a deep-pocketed adversary may not be deterred by the costs, because by attacking in this fashion he is getting side-benefits by harming BTC.
Perhaps, we could run a quantum experiment and determine if human consciousness could limit the number of transactions being processed by the network.
Everyone... now, please, close your eyes and imagine spam transactions going away... imagine strings of 128kB blocks... your rasb pi gently processing all the most important financial settlement contracts in the world... Imagine a world, without competition, where people will pay more and more just to use our holy ledger, investors lining up to buy a piece of a network that has already had its best years of growth. Together, we
can do this.